Let me just briefly run down how I'm handling each of the above situations, so that if I'm making some sort of conceptual mistake, someone can correct me on it.

First, there's the situation where you have one weapon with Flurry. This is very simple; The probability of a given swing having reduced speed is equal to the probability of any of the three previous swings having crit. In other words, you take the probability that

*none*of the previous three swings crit times the base weapon speed, plus the complement of that probability times the Flurry-reduced speed (speed/1.3).

Now, if you have Flurry with Windfury, then any of the three previous swings may have procced Windfury, and if any of those extra swings crit, Flurry procced. I approach this by first calculating the probability, on any given initial swing, either that the initial swing crits or that a Windfury swing occurs and crits. In other words:

1 - ((1-Crit%)*(1-(Crit%+Hit%+Glance%)*0.20*Crit%)*(1-(Crit%+Hit%+Glance)*0.20*Crit%))

That's the probability that any given swing gets at least one crit. Then you simply substitute that in the formula for the first situation.

Now, when you have Dual Wield with no Windfury, as long as you can guarantee that the main and offhand have the same chances to crit/hit/etc. (i.e. you have the same weapon skill with both), the formula stays exactly the same. Same if you have Windfury on both weapons.

But...what if you have Windfury, say, only on the main hand, and something else on the offhand? Now, for any given swing, it's possible that some of the preceding attacks were Windfury-capable, and the rest were not. In that case, how can you know how many? Can we do some sort of probability-based average (in which case, please forgive me, as I horribly fail at more advanced probability stuff)? Or can/should we approach the model in a completely different fashion? Would it simply be more plausible to write a program to simulate the situation for different weapon speeds and output averages over extremely long time periods instead (in which case, I would very easily be capable of such a thing)?

I appreciate any help I can get on this one. It kind of reminds me of the whole thing about what fraction of a main hand swing you "gain" when your offhand procs sword spec (which I was also never able to figure out for myself).